1. Field of the Invention
This invention relates to a solder head control mechanism which includes a controller to actuate an acoustic coil linear servomotor, a decoder and a solder head means for controlling the movement of a solder head to perform a work desired.
2. Description of the Prior Art
Conventional solder means mostly use a rotational servomotor to drive a gear set for moving the solder head to a desired position. The solder head is moved by means of a transmission means. The rotation of the servomotor consumes energy. Furthermore feedback speed and position signal depend on rotation value. Control of the solder head depends on a half-loop control that will cause some deviation. Its accuracy is poorer than a full-loop control. Moreover a conventional servo actuator has a fixed amplifying factor. It is not flexible or versatile for different environments and situations such as different speed requirements, different quality requirements, and total process needs. There is still room for improvement.
SUMMARY OF THE INVENTION
In view of aforesaid disadvantages, it is therefore an object of this intentional to provide a control module that employs an acoustic coil linear servomotor and a solder head means to directly drive a solder head. The solder head means further couples with a speed sensor and a position sensor to form a full loop control. An amplification selectional control is further included to divide the amplification of the acoustic coil linear servomotor into several segments to meet system control needs.
The solder head according to this invention is a movable element controlled by an acoustic coil linear servomotor and may vibrate reciprocally in a vector Z axis normal to a plane defined by vector axes X and Y. There is a position sensor to measure the position of the solder head. The position sensor uses a curved shaped photo ruler to match the solder head for shortening measuring time. Conventional linear photo ruler needs a conversion process to measure a non-linear solder head movement and takes longer time. The measurement method is known in the art and forms no part of this invention, thus is omitted here.
The position sensor transmits position signals to a main controller, which in turn issues instructions to move a vector X-Y axis platform so that the solder head may move in X-Y-Z axis concurrently. This invention does not include the control of solder head motion in X-Y axis. This invention does include a controller for controlling the movement of acoustic coil linear servomotor according to proportional integration differential (PID) rules. The motion path is mapping vibration oscillation. There is also a current output actuator to receive signals from the controller and to output current for driving the acoustic coil linear servomotor which in turn moves the solder head to a position desired.